The present invention relates to ink jet printing and in particular discloses an iris motion ink jet printer.
The present invention further relates to the field of drop on demand ink jet printing.
Many different types of printing have been invented, a large number of which are presently in use. The known forms of printing have a variety of methods for marking the print media with a relevant marking media. Commonly used forms of printing include offset printing, laser printing and copying devices, dot matrix type impact printers, thermal paper printers, film recorders, thermal wax printers, dye sublimation printers and ink jet printers both of the drop on demand and continuous flow type. Each type of printer has its own advantages and problems when considering cost, speed, quality, reliability, simplicity of construction and operation etc.
In recent years, the field of ink jet printing, wherein each individual pixel of ink is derived from one or more ink nozzles has become increasingly popular primarily due to its inexpensive and versatile nature.
Many different techniques of ink jet printing have been invented. For a survey of the field, reference is made to an article by J Moore, xe2x80x9cNon-Impact Printing: Introduction and Historical Perspectivexe2x80x9d, Output Hard Copy Devices, Editors R Dubeck and S Sherr, pages 207-220 (1988).
Ink Jet printers themselves come in many different forms. The utilization of a continuous stream of ink in ink jet printing appears to date back to at least 1929 wherein U.S. Pat. No. 1,941,001 by Hansell discloses a simple form of continuous stream electrostatic ink jet printing.
U.S. Pat. No. 3,596,275 by Sweet also discloses a process of a continuous ink jet printing including the step wherein the ink jet stream is modulated by a high frequency electro-static field so as to cause drop separation. This technique is still utilized by several manufacturers including Elmjet and Scitex (see also U.S. Pat. No. 3,373,437 by Sweet et al)
Piezoelectric ink jet printers are also one form of commonly utilized ink jet printing device. Piezoelectric systems are disclosed by Kyser et. al. in U.S. Pat. No. 3,946,398 (1970) which utilizes a diaphragm mode of operation, by Zolten in U.S. Pat. No. 3,683,212 (1970) which discloses a squeeze mode of operation of a piezoelectric crystal, Stemme in U.S. Pat. No. 3,747,120 (1972) discloses a bend mode of piezoelectric operation, Howkins in U.S. Pat. No. 4,459,601 discloses a piezoelectric push mode actuation of the ink jet stream and Fischbeck in U.S. Pat. No. 4,584,590 which discloses a shear mode type of piezoelectric transducer element.
Recently, thermal ink jet printing has become an extremely popular form of ink jet printing. The ink jet printing techniques include those disclosed by Endo et al in GB 2007162 (1979) and Vaught et al in U.S. Pat. No. 4,490,728. Both the aforementioned references disclosed ink jet printing techniques which rely upon the activation of an electrothermal actuator which results in the creation of a bubble in a constricted space, such as a nozzle, which thereby causes the ejection of ink from an aperture connected to the confined space onto a relevant print media. Printing devices utilizing the electro-thermal actuator are manufactured by manufacturers such as Canon and Hewlett Packard.
As can be seen from the foregoing, many different types of printing technologies are available. Ideally, a printing technology should have a number of desirable attributes. These include inexpensive construction and operation, high speed operation, safe and continuous long term operation etc. Each technology may have its own advantages and disadvantages in the areas of cost, speed, quality, reliability, power usage, simplicity of construction operation, durability and consumables.
There is disclosed herein an ink jet nozzle assembly including a nozzle chamber formed on a substrate, the nozzle chamber having an ink ejection port and a projecting rim formed integrally with the nozzle chamber about said ink ejection port.
There is further disclosed herein an ink jet nozzle assembly including:
a nozzle chamber having an inlet in fluid communication with an ink reservoir and a nozzle through which ink from the chamber can be ejected;
the chamber including a fixed portion and a movable portion configured for relative movement in an ejection phase and alternate relative movement in a refill phase;
an expanding, flexible arm and a rigid arm each connected with the movable portion and cooperating to effect periodically said relative movement; and
the inlet being positioned and dimensioned relative to the nozzle such that ink is ejected preferentially from the chamber through the nozzle in droplet form during the ejection phase, and ink is alternately drawn preferentially into the chamber from the reservoir through the inlet during the refill phase.
Preferably the movable portion includes the nozzle and the fixed portion is mounted substrate.
Preferably the fixed portion includes the nozzle mounted on a substrate and the movable portion includes a vane unit.
Preferably a plurality of said vane units arranged around said ink ejection port, said vane units each attached to a said expanding, flexible arm and a said rigid arm such that upon activation, a volume of ink in the nozzle chamber adjacent said ejection port is pressurized so as to cause the ejection of ink from said ink ejection port.
Preferably said flexible arms comprise a conductive heater material encased within an expansion material having a high coefficient of thermal expansion.
Preferably said conductive heater material is constructed so as to form a concertina upon expansion of said expansion material.
Preferably said heater material is of a serpentine form and forms a concertina upon heating so as to allow substantially unhindered expansion of said expansion material during heating.
Preferably said vane units are arranged annularly around said ink ejection port.
Preferably said vane units operate as an iris around said ink ejection port.
Preferably the vane units are of a semi-circular form.
Preferably the assembly comprises four said vane units.
Preferably said expansion material comprises substantially polytetrafluoroethylene.
Preferably said conductive heater material comprises substantially copper.
Preferably an outer surface of said chamber includes a plurality of etchant holes provided so as to allow a rapid etching of sacrificial layers during construction.